Automatic control for carburetors



June 15' 1926. 1,588,727

F. F. HENRIOT AUTOMATIC CONTROL FOR CARBURETORS Filed August 10, 1922INVENTOR ATTORNEY Patented June 15, 1926.

UNITED STATES PATENT errce.

FLOYD r. nnnnror, or NEAR wINLo x, wnsrrmeron.

AUTOMATIC con'rnor. ron cAnnnnn'rons.

Application filed August 10, 1922. Serial No. 580,928. I

the engine has been running long enough to be heated to its normalrunning temperature, l thus permitting the easy starting of the enginewithout interfering with its economy when in full operation. Otherobjects are to provide such a device which is simple and cheap to makeand easy'to install.

I attain these and other objects by the devices and arrangementsillustrated in the accompanying drawings, in which Fig. 1 is a viewshowing my device mounted on anengine and showing a portionof 2O mostat;Fig. 3 is a section of a part of the carburetor showing the needle valverod; and Fig. 4 is a cross section of the exhaust manifold showing thethermostat clamped thereto.

Similar numerals of reference refer to similar parts throughout theseveral views.

When an engine'is cold it requires a richer mixture of gasoline in theintake air than it does for economical operation when it has reached itsnormal operating temperature. Therefore an automatic mechanism will haveto open up the needle valve, which controls the amount of gasolineadmitted to the carburetor, when the engine is cold and then partiallyclose it again as it heats up.

However, the exl ientof such opening of the needle valve sho myapparatus closes it down again it should bring it only to the adjustmentat. which the engine operates most economically. In the drawings I havevery greatly exaggerated the motion, of the needle valve,-caused by myapparatus but it is to be. understood that this is done for the purposeof clearness, since the motion is actually about one sixtg fourth of aninch and therefore would not e distin uishable in the drawings.

Retgarring now to the drawings, the carburetor 1 is shown as connectedto the intake pipe 2 leading to the manifold 3 of the engine in theusual manner. The carburetor has a.cap 4 secured to its upper side and ascrew-threaded hole passes therethrough as usual. A manually operatedadjusting the exhaust and intake systems thereof; Fig, 2 is a sideelevation of the controlling ther Id be very small and when sleeve 5screws in the hole enters the interior of sleeve 5 is turned by and islocked in any in the cap land the carburetor. This the flange?) thereonadjusted position by the lock nut 7 screwing on its shank and engagingthe top surface of the cap 4. The sleeve 5 has a central hole throughit.

The needle valve V ofa long rod 9 and controls the gasoline passage 10in the carburetor 1, opening said passage as it is raised therefrom. Acollar 11 is secured to the rod 9 below the lower end of the sleeve 5and is adapted to limit the upward motion of the rod in the sleeve andthus limit the extent to which the appa-' ratus may open u the passage10 when the engine is cold.. similar collar 12 is socured to the rod 9immediately above the upper end of the sleeve 5 and is adapted to limitthe downward movement ofthe rod in the sleeve thus closing the passage10 to the extent permitted by the adjustment of the sleeve 5, it beingintended that when the rod 9 is lowered the needle valve 8 will be 8 isformed on the end running of the point is adjusted by turning the sleeve5 in the cap 4. I

A thermostat 13 is formed of a strip of brass 14 riveted at variouspoints to the upper side of a similar strip of iron 15. One end of thisthermostat 13 is riveted to a cross bar 16. The thermostat 13 is clampedbetween the cross bar 16 and the exhaust manifold 17 of the engine. by aU-bolt 18, which encircles the lower part of the manifold and whichpasses through holes in the ends of the cross bar 16. Suitable nuts arescrewed on the ends of the U-bolt and bear against the upper surface ofthe cross bar 16.

particular engine, and this This thermostat 13 extends to a pointthreaded at its upper end and this art passes through the slot in the.free end 0 the said thermostat 13. The rod 9 isadjustably secured to thefree end of the thermostat 13 by being clamped between the lower andupper nuts 19 and 20, respectively, screwed on it and this adjustment issecured from being inadvertently changed by a lock nut 21 engaging thesaid nut 20.

y device 0 crates in the followin manmere-The coegcient of ex ansion 0%brass being greater than that 0 iron, it follows that for a given changein temperature the I brass will change its length more than the irondoes and therefore, since the two strips 14.- and 15 are rivetedtogether at various places, the thermostat formed by them changes itscurvature with changes in its temperature. But one end of thisthermostat is held fast to the exhaust manifold 17 by the clamp andtherefore the free end tends torise as the temperature of the thermostatfalls and to press downward as the temperature rises. This action iscommunicated to the rod 9 fastened to it, and therefore when the engineis cold the thermostat pulls the rod 9 upward until the lower collar 11engages the lower end of the sleeve 5, thus opening the passage 10 inthe carburetor a definite amount depending on the free motion of the rod9 permitted by the twofixed collars 11 and 12 and increasing the supplyof gasoline when the engine is started (under this condition the rod 9is in tension and holds the thermostat from further motion upward);while, as the exhaust manifold 17 becomes heated by the high temperatureof the exhaust gases, it gradually duces the upward pullon the rod 9;then,

when the temperatureof the thermostat has become high enough, the end ofthe lever actually presses down on the rod 9 moving it downward untilthe collar 12 engages the upper side of the sleeve 5, thus closing thepassage 10 to the normal operating position. In this condition the rod 9is in compression and holds the thermostat from further motion downward.It should be noted that the allowed motion of the rod and of the end ofthe thermostat is much smaller than the motion of the thermostat wouldbe if it were free from the rod; therefore the said thermostat, in beingconfined. to such limited motion, is actually absorbing some of themotion which it otherwise would make. This is purposely provided inorder to give an appreciable time after the engine, is started beforethe valve is closed to normal and to cause sufficient delay after theengine is stopped, or the gasoline is shut off, before the valve opensup. This prevents the control being too sensitive and makes it open theneedle valve only after the engine has been standing long enough to cool0H, and also gives the engine time to warm up effectively before closingthe valve to its normal operating position.

There are several ways in which this apheats the thermostat 13 andreparatus could he changed without altering the essential ideas therein;for instance, other metals than brass and iron might be used, theessential point being that they have different coefficients ofexpansion, also the means of attaching the thermostat to the exhaustmanifold may be altered, also a single collar on the rod may besubstituted for the two collars described if it operates between twosuitable stops on the sleeve, also the means of attaching the rod to thethermostat may be changed.

Having described my invention, what I claim is In a device of the classdescribed, the combination with an exhaust manifold; a carburetor; agasoline passage therein and provided with a valve seat; a screw sleevemounted in and passing through the shell of the carburetor, coaxial withthe valve seat, and rotatable in the shell, thereby providing positiveadjustmenttherein relatively to the said valve seat; a needle valve, adjacent to but separated from said valve seat, having a stem extendingcoaxially through the sleeve, said valve coacting with the valve seatwhereby the extent of opening of the gasoline passage is controlled bythe adjustment of said needle valve closer to or further from said seat;two limiting collars on said valve stem, one on each side of said screwsleeve and closely adjacent thereto, whereby free but limited axialmovement of the valve stem is permitted relative to the adjustedposition of the sleeve but all other axial motion of the stem isprevented, and whereby the normal openin of said needle valve iscontrolled by the ad ustment of said screw sleeve in the carburetorshell; and a thermostat fixedly mounted at one end to the exhaustmanifold whereby it is heated, its free end being secured to the outerend of the valve stem, said thermostat being positively stopped frommotion in either direction, under the influence of the heating orcooling manifold, by the positive engagement of one or the other of saidlimiting collars with the adjusted screw sleeve, whereby the needlevalve is slightly opened beyond its normal adjusted position when themanifold is cool and remains fixed at said extreme open position untilthe manifold has been heated an appreciable time, and is then closedthereby to said normal adjusted position.

FLOYD F. HENRIOT,

